One application in which a first element must be positioned by remote control with respect to a second element, is in the initial coupling of a pair of space vehicles, as in the initial coupling of a space shuttle to an orbiting satellite. A grappling claw lying at the end of a long manipulator boom extending from the space shuttle, is manipulated so that the claw is in line with the grappling fixture, and with the plane of the claw parallel to the plane of the grappling fixture. The claw then can approach slightly closer to the fixture and four jaws on the claw can close over four corresponding strikers on the fixtures, to securely connect the end of the boom to the fixture on the satellite. The lateral positioning of the claw substantially in line with the fixture normally can be easily accomplished as by an operator viewing them from a distance, but sensing the orientation of the claw about yaw and pitch axis and sensing distance along the line of sight, are difficult to accomplish by mere viewing from a distance. A relatively simple system for sensing the orientation and line-of-sight distance of a pair of elements would aid in the manipulation of a claw designed to grasp a fixture, as well as in other remote control applications.